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                            <div style="color:gray; word-break: break-all; font-size:12px;">原英文版地址: <a href="https://www.elastic.co/guide/en/elasticsearch/reference/7.7/mapping-boost.html" rel="nofollow" target="_blank">https://www.elastic.co/guide/en/elasticsearch/reference/7.7/mapping-boost.html</a>, 原文档版权归 www.elastic.co 所有<br/>本地英文版地址: <a href="../en/mapping-boost.html" rel="nofollow" target="_blank">../en/mapping-boost.html</a></div>
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<strong>重要</strong>: 此版本不会发布额外的bug修复或文档更新。最新信息请参考 <a href="https://www.elastic.co/guide/en/elasticsearch/reference/current/index.html" rel="nofollow">当前版本文档</a>。
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<span class="breadcrumb-node"><code class="literal">boost</code></span>
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<h2 class="title">
<a id="mapping-boost"></a><code class="literal">boost</code><a class="edit_me edit_me_private" rel="nofollow" title="Editing on GitHub is available to Elastic" href="https://github.com/elastic/elasticsearch/edit/7.7/docs/reference/mapping/params/boost.asciidoc">edit</a>
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<p>Individual fields can be <em>boosted</em> automatically — count more towards the relevance score — at query time, with the <code class="literal">boost</code> parameter as follows:</p>
<div class="pre_wrapper lang-console">
<pre class="programlisting prettyprint lang-console">PUT my_index
{
  "mappings": {
    "properties": {
      "title": {
        "type": "text",
        "boost": 2 <a id="CO333-1"></a><i class="conum" data-value="1"></i>
      },
      "content": {
        "type": "text"
      }
    }
  }
}</pre>
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<div class="console_widget" data-snippet="snippets/743.console"></div>
<div class="calloutlist">
<table border="0" summary="Callout list">
<tr>
<td align="left" valign="top" width="5%">
<p><a href="#CO333-1"><i class="conum" data-value="1"></i></a></p>
</td>
<td align="left" valign="top">
<p>Matches on the <code class="literal">title</code> field will have twice the weight as those on the
<code class="literal">content</code> field, which has the default <code class="literal">boost</code> of <code class="literal">1.0</code>.</p>
</td>
</tr>
</table>
</div>
<div class="note admon">
<div class="icon"></div>
<div class="admon_content">
<p>The boost is applied only for term queries (prefix, range and fuzzy queries are not <em>boosted</em>).</p>
</div>
</div>
<p>You can achieve the same effect by using the boost parameter directly in the query, for instance the following query (with field time boost):</p>
<div class="pre_wrapper lang-console">
<pre class="programlisting prettyprint lang-console">POST _search
{
    "query": {
        "match" : {
            "title": {
                "query": "quick brown fox"
            }
        }
    }
}</pre>
</div>
<div class="console_widget" data-snippet="snippets/744.console"></div>
<p>is equivalent to:</p>
<div class="pre_wrapper lang-console">
<pre class="programlisting prettyprint lang-console">POST _search
{
    "query": {
        "match" : {
            "title": {
                "query": "quick brown fox",
                "boost": 2
            }
        }
    }
}</pre>
</div>
<div class="console_widget" data-snippet="snippets/745.console"></div>
<div class="warning admon">
<div class="icon"></div>
<div class="admon_content">
<h3>Deprecated in 5.0.0.</h3>
<p>Index time boost is deprecated.  Instead, the field mapping boost is applied at query time. For indices created before 5.0.0, the boost will still be applied at index time.</p>
</div>
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<div class="warning admon">
<div class="icon"></div>
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<h3>Why index time boosting is a bad idea</h3>
<p>We advise against using index time boosting for the following reasons:</p>
<div class="ulist itemizedlist">
<ul class="itemizedlist">
<li class="listitem">
You cannot change index-time <code class="literal">boost</code> values without reindexing all of your
documents.
</li>
<li class="listitem">
Every query supports query-time boosting which achieves the same effect. The
difference is that you can tweak the <code class="literal">boost</code> value without having to reindex.
</li>
<li class="listitem">
Index-time boosts are stored as part of the <a class="xref" href="norms.html" title="norms"><code class="literal">norm</code></a>, which is only one
byte.  This reduces the resolution of the field length normalization factor
which can lead to lower quality relevance calculations.
</li>
</ul>
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